Dís is supposed to be stern in a way that makes people be a bit scared of her. I would like to suggest Glenn Close for this role, I think she'd be great. https://www.imdb.com/name/nm0000335/
Known for: Game of Thrones, Philomena, In the Heart of the Sea
www.imdb.com
Age: 55
Height: 5'5"
Roles: Catelyn Stark in Game of Thrones, Margot Al-Harazi in 24: Live Another Day, Margaret Beaufort in The White Princess, Cassius in Bridge Theater's Julius Caesar
She can play both positive and negative maternal figures.